The water scale settling (of CaCo3, MgCo3, CaSiO3, ferric oxides etc.) is formed on the heat surfaces of heat-engineering equipment (boilers, heat exchangers, evaporators, coolers etc.) at its work.
In this case the heat transfer is deteriorated because the thermal conductivity of the water scale is tens times less than this of metal, the efficiency and the capacity of the equipment are declined because the scale layer of I mm gives rise to fuel overturning of 2-2.5% and at the scale layer of 5 mm it may run up to 8-10%, because of overheating and corrosion of the metal under scale layer, the service life of the tube metal is reduced and damage (flaws, bulges, ruptures) may occur.
Softening of used water requires considerable means for building and servicing of chemical water treatment plants. Water softening through the agency of ion-exchange materials or the use of complexions in open heat supplies systems and at water heating for hot water supply is uneconomical and ecologically harmful.
Ultrasonic method of the water scale prevention is based on studies that have been conducted in the USSR since the late 1930s. The widespread adoption of ultrasonic technologies began at 1950s-1960s, but only is recent years the equipment that combined high effectiveness and reliability and moderate cost has been elaborated.
Under the action of the weak ultrasonic vibration, the multitude of constantly shifting crystallising centres are generated in water, resulting in difficulty of scale crystals growing and settling on heat exchange surfaces of equipment. Microfissures formed in the scale layer under the action of ultrasonic vibration, accumulating, break up existing settling and the unit appears descaled. Slime is removed by water flow or blow-through.
This is the most efficient and universal of the reagents physical method. It is economical, ecologically clean, safe in service for equipment and personnel. It may be combined with the use of complexions and the chemical water treatment.
Ultrasonic technique - INLAB offers the following units for water scale control: |
I-1M |
I-1MX |
I-2 |
Design: | generator and emitter in common body | generator and emitter are in separate bodies and connected with cable in flexible metal pipe of 6.2 m in length | generator is made in the form of separate two-channel instrument unit with two emitters |
Consumed power, W: | 30 | 70 | 380 |
Voltage, V 50-60 Hz: | 220 ± 10% | 220 ± 10% | 220 ± 10% |
Type of ultrasound emitter: | magnetostrictive | ||
Mass, no more, kg: | 2,5 | 5 | 22 |
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